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Title:	Synthesis, characterization and biological study of thiophene thiosemicarbazone ligands and their transition metal complexes
Authors:	Safa Faris Kayed (P35458)
Supervisor:	Yang Farina Abdul Aziz, Prof. Dr.
Keywords:	Thiosemicarbazones-Synthesis Thiophenes Dissertations, Academic -- Malaysia
Issue Date:	29-Mar-2012
Description:	Considerable interest has been aroused for semicarbazones and thiosemicarbazones and their transition metal complexes because of their wide variety of biological activity. A series of N2 and N4 substituted 2-acetylbenzothiophene semicarbazone and thiosemicarbazone ligands namely 2-acetylbenzothiophene 3-thiosemicarbazone a, 2-acetylbenzothiophene 4-methyl-3-thiosemicarbazone b, 2-acetyl-benzothiophene 4-ethyl-3-thiosemicarbazone c, 2-acetylbenzothiophene 4-phenyl-3-thiosemicarbazone d, 2-acetylbenzothiophene 4-cyclohexyl-3-thiosemi-carbazone e, 2-acetylbenzo-thiophene 4,4-dimethyl-3-thio-semicarbazone f, 2-acetylbenzothiophene 2-methyl-3-thiosemicarbazone g, 2-acetylbenzothiophene 3-semicarbazone h and 2-acetylbenzothiophene 4-phenyl-3-semicarbazone i were successfully synthesized and characterized. The single crystal X-ray diffraction analysis indicated that in the solid state the free ligands exist in the thione form with C=S bond distance around 1.68 Å. The ligands a, b, c, d and e formed complexes with zinc(II), cadmium(II), nickel(II), palladium(II) and copper(II) metal ions. Zinc(II), cadmium(II) and nickel(II) complexes have the molecular formula [ML2] and palladium(II) complexes have the molecular formula [PdCl2L], L is the corresponding ligand. Copper(II) complexes have the different formulas; [CuSO4L2]2, [CuL2H2O]2 and [CuSO4L], L is the corresponding ligand. The ligand g formed complexes with nickel(II), palladium(II) and copper(II) metal ions. Nickel(II) and palladium(II) complexes have the molecular formula [M2Cl4L].6H2O and copper(II) complex has the molecular formula [Cu2(SO4)2L].6H2O, L is the corresponding ligand. The elemental analysis results for the complexes are in good agreement with the values calculated for the predicted molecular formulas. The spectroscopic analysis of the zinc(II), cadmium(II) and nickel(II) complexes of a, b, c, d and g indicated that the ligand coordinated to the metal centres as a bidentate ligand through the thiolate sulphur and the azomethine nitrogen to give a distorted square planar arrangement around nickel(II) centres and a distorted tetrahedral arrangement around zinc(II) and cadmium(II) centres. The Zn-S and Ni-S bonds distance is around 2.15 Å, while the Zn-N and Ni-N bonds distance is around 1.94 Å. However, palladium(II) complexes showed preference for the thione form of the thiosemicarbazone ligands and the structure of the complexes is close to a distorted square planar. The corresponding ligands showed different behaviours with copper(II) complexes. The ligands c, d and e were coordinated with copper(II) ions in the thiol form. The complexes were dimeric and the geometry surrounding the copper centres is close to a distorted octahedral. While, the ligands a and b were coordinated with copper(II) ions in the thione form. Two copper complexes of b were isolated, one is dimeric 6-coordinated and the other is monomeric 4-coordinated. The ligand g was deduced to act as a tetradentate ligand in the thione form with nickel(II), palladium(II) and copper(II) ions. Four coordinated binuclear structures have been proposed for these complexes. In vitro antimicrobial tests showed that some of the prepared complexes had strong inhibitory effect. The nickel(II) complex of a and the copper(II) complex of e showed more activity than Tobramycin against G(+) Staphylococcus aureus with an inhibition zone 13 mm and 14.5 mm, respectively. Further more, The nickel(II) complex of a showed more activity than Nystatin against Aspergillus niger with an inhibition zone 22 mm. The cytotoxic activity for the prepared copper(II) complexes was evaluated against human hepatocellular carcinoma cells and Chang liver cells which showed that the complexes possessed a remarkable cytotoxic effect.,Certification of Masters/ Doctorial Thesis" is not available
Pages:	384
Call Number:	QD305.T45K389 2012 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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